1. Field of the Invention
The present invention relates to a head for an air pump.
2. Description of the Related Art
A floor pump is an air pump that is commonly known. While the floor pump has the advantage of enabling the user to pump an item to be inflated in an efficient way, it needs a large storage space, and carrying it is not easy. Therefore, it is not convenient for the user to carry a floor pump with him. Then, a portable air pump is invented, and it finds favor with bicycle riders. Generally, a portable air pump includes a hose exposed outside the body of the portable pump and a footstand which is retractable. Then, a mini pump is invented. Generally, a mini pump has no hose attached to and exposed outside the body of the mini pump in order to achieve a compact volume. Moreover, a mini pump generally has a flush overall outlook. Therefore, a mini pump has the advantage of having an appealing appearance, and it is convenient for the user to carry the mini pump with him.
As set forth, air pumps are classified into three categories: a floor pump, a mini pump and a frame floor pump. The floor pump generally has a large cylinder for allowing a large volume of air to be pumped out per stroke. Furthermore, the floor pump has a pedal and a handle, and the user can step on the pedal and hold the handle during the operation of the floor pump. The mini pump has a smaller volume relative to the floor pump so that it is convenient and easy for the user to carry the mini pump. When operating the mini pump, the user grips a cylinder of the mini pump in one hand and grips a nozzle head of the mini pump in another hand. However, it is laborious to operate the mini pump, because it does not provide a fulcrum during the operation thereof. The frame floor pump combines the advantages of the floor pump and the mini pump. It has a footstand and a handle which can be pivoted from a position aligned with a cylinder of the frame floor pump to a position perpendicular to the cylinder during the operation of the frame floor pump, and user can step on the pedal and grip on the handle to achieve an effort-saving operation. Additionally, it has a small volume so that it can be carried easily.
U.S. Pat. No. 6,135,733 shows a portable air pump. The pump includes a head, and the head includes a compartment defined therein. The compartment includes an air outlet port defined at a side thereof, and includes a nozzle and a plug disposed therein. The nozzle and the plug are retained in the compartment by an end cap mounted in the air outlet port. It is appreciated that the head is of an enclosed configuration so the nozzle and the plug enclosed in the head are prevented and protecated from dust particles, thereby their use life will not be shortened quickly. While the plug is adapted to push the nozzle to engage with the head to create an air-tight condition between the nozzle and the head, the plug can not automatically engage with the nozzle securely. It is, however, required that the user continually push the head to achieve an air-tight condition with the nozzle while carrying out an inflating operation.
U.S. Patent Publication No. 2007/0148023 shows an air pump including a head, a plug slidably disposed in a compartment defined in the head, a pivoting member mounted to a first distal end of the head and abutting against an end of the sliding member, a nozzle disposed on another end of the sliding member opposite to the pivoting member, and an end cap engaged with a second distal end of the head. The compartment extends from the first distal end to the second distal end. The sliding member and the nozzle are prevented from disengagement from the head as the pivoting member restrains them from escaping out of the first distal end thereof, and the end cap restrains them from escaping out of the second distal end thereof, respectively. While the pivoting member is adapted to push the plug and the nozzle sequentially in order to enable the nozzle to automatically engage with the head securely and in an air-tight condition, the head can not protect the plug and the nozzle from contact with dust particles, which would shorten their use life quickly. Another drawback is that this pivoting member protrudes prominently and is not aesthetic pleasing. It is acknowledged that other references, for example, U.S Patent Publication No. 2008/0308158 and U.S. Pat. No. 5,762,095, suffer the same problem as neither of the pump heads can preclude dust particles from damaging parts disposed therein.
The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art.